Objectives: To analyze the Nogo-P3 component of event-related potential (ERP) in the process of visual acuity processing, to provide electrophysiological evidence for objective evaluation of visual acuity.
Methods: Twenty-six subjects with no other ocular diseases except for ametropia were recruited, and all subjects had uncorrected visual acuity both eyes 1/10 (evaluated using Monoyer chart). Block letter E with different visual angles and directions were used as graphic stimuli. The Go/Nogo paradigm was used for ERP studies. The visual angle of Go stimulation angle was 1°15', Nogo stimuli were 1°15', 55', 24' and 15'. The visual acuity test was performed on each of the two naked eyes separately in all subjects, and the characteristics of the Nogo-P3 component were analyzed.
Results: The latency of Nogo-P3 showed no difference between the stimuli of 1°15' and 55', and between Nogo stimulation angle 24' and 15'. There was significant difference between Nogo stimulation angle 1°15' and 24', and between Nogo stimulation angle 1°15' and 15' (P<0.05). There was significant difference between Nogo stimulation angle 55' and 24', and between Nogo stimulation angle 55' and 15' (P<0.05). No significant differences were observed in the Nogo-P3 amplitude among Nogo stimulation.
Conclusions: In the Go/Nogo paradigm, Nogo-P3 can reflect the cognitive response of subjects to Nogo stimulation, which can be used for objective evaluation of visual acuity.
目的: 分析视敏度加工过程中事件相关电位（event-related potential，ERP）的Nogo-P3，为视敏度的客观评定提供电生理学依据。方法: 选择除屈光不正外无其他眼病的受试者26名，双眼裸眼视力均为0.1，选用不同视角大小、不同开口方向的“E”图形作为刺激图片，ERP实验采用视觉Go/Nogo范式，Go刺激视角为1°15′，Nogo刺激视角分别为1°15′、55′、24′、15′，对被试者裸眼视力进行测试，分析Nogo-P3的特征。结果: Nogo-P3潜伏期在Nogo刺激视角1°15′与55′、Nogo刺激视角24′与15′相比，差异无统计学意义；Nogo刺激视角1°15′与24′、15′相比，差异有统计学意义（P<0.05）；Nogo刺激视角55′与24′、15′相比，差异有统计学意义（P<0.05）。Nogo-P3波幅在各Nogo刺激视角间差异无统计学意义。结论: 在Go/Nogo范式下，Nogo-P3能够反映被试者对Nogo刺激的认知反应，可用于视敏度的客观评估。.
Keywords: Nogo-P3; ametropia; amplitude; event-related potential; forensic medicine; latency; vision; visual acuity.